Venous air embolism related to the use of central catheters revisited: with emphasis on dialysis catheters

Abstract

Venous air embolism is a dreaded condition particularly relevant to the field of nephrology. In the face of a favourable, air-to-blood pressure gradient and an abnormal communication between the atmosphere and the veins, air entrance into the circulation is common and can bring about venous air embolism. These air emboli can migrate to different areas through three major routes: pulmonary circulation, paradoxical embolism and retrograde ascension to the cerebral venous system. The frequent undesirable outcome of this disease entity, despite timely and aggressive treatment, signifies the importance of understanding the underlying pathophysiological mechanism and of the implementation of various preventive measures. The not-that-uncommon occurrence of venous air embolism, often precipitated by improper patient positioning during cervical catheter procedures, suggests that awareness of this procedure-related complication among health care workers is not universal. This review aims to update the pathophysiology of venous air embolism and to emphasize the importance of observing the necessary precautionary measures during central catheter use in hopes of eliminating this unfortunate but easily avoidable mishap in nephrology practice.

Cortical Blindness and Altered Mental Status following Routine Hemodialysis, a Case of Iatrogenic Cerebral Air Embolism

“…Additional case reports have noted pneumocephaly from injected air via peripheral IV placement [ 19 ]. Risk factors for developing cerebral air embolus during invasive vascular manipulations include hypovolemia, increased intrathoracic pressure in deep inspiration, and mobile or upright patients [ 2 , 15 , 20 ]. In this patient, the air embolus likely traveled retrogradely through the patient's vascular matrix into the cerebral vessels when the patient was seated upright during dialysis.…”

“…The clinical symptoms of cerebral air embolus are myriad and can exhibit symptoms resembling stroke or acute cerebral infection. Fever, headache, abnormal ocular movements, vision loss, altered level of consciousness, hypotension, seizures, paralysis, and abnormal motor function have all been previously described [ 20 – 22 ]. A high index of suspicion must be held for air embolus in high risk patients, as the diagnosis relies mainly on the clinical picture.…”

“…Air emboli may cause hemodynamic instability and should be addressed in patients with cardiopulmonary distress as well as cerebral symptoms. For other air embolism conditions, it has been suggested that positioning the patient in head-down Trendelenburg position would be beneficial in preventing intracardiac air from traveling out to the lungs by trapping it in the apex of the right ventricle; however, subsequent studies have demonstrated lack of clinical improvement with such maneuvers [ 20 ]. Patients with cerebral air embolism should especially avoid Trendelenburg positioning as this may potentially exacerbate cerebral edema [ 20 ].…”

Cerebral air embolism from a Central Venous Catheter: A timely reminder of the importance of rapid diagnosis

“…More commonly, air can travel to the heart while the patient is in the supine position and pass into the ventricle and lungs, causing dyspnoea, cough, chest tightness and arrhythmias. It can also migrate to the arterial side from the venous side via intracardiac shunts (eg, patent foramen ovale) or intrapulmonary shunts (eg, arteriovenous malformations, intrapulmonary physiological shunts) 6. Physiologically, pulmonary capillaries can filter out air bubbles, thereby protecting the venous and arterial circulations.…”

Complications of Implanted Nonbiologic Devices—An Overview

“…Though the practice of disconnecting a catheter is frequent, this complication is unfortunately underrecognized. [36][37][38][39] Long-term outcome is unfavorable, especially when the central nervous system is involved, with mortality rate as high as 25%. 40 Special precautions when handling the catheters have been shown to reduce this complication.…”